Method for controlling an electric drive motor of an electrically drivable bicycle

Abstract

A method for controlling an electric drive motor of an electrically drivable bicycle includes determining a cadence of a rider of the bicycle, and operating the electric drive motor under specification of (i) a first predefined target speed for the electric drive motor, which is lower than the cadence of the rider, and (ii) a first predefined torque for the electric drive motor, when the determined cadence of the rider exceeds a predefined cadence threshold value. The method further includes operating the electric drive motor under specification of (i) a second predefined target speed for the electric drive motor, which is higher than the first target speed, and (ii) a second predefined torque for the drive motor, when a rider torque exerted by the rider on a drive train of the bicycle exceeds a first predefined rider torque threshold value.

The invention claimed is: 
     
       1. A method for controlling an electric drive motor of an electrically drivable bicycle comprising:
 determining a cadence of a rider of the bicycle; 
 operating the electric drive motor under specification of (i) a first predefined target speed for the electric drive motor, which is lower than the determined cadence of the rider, and (ii) a first predefined torque for the electric drive motor, when the determined cadence of the rider exceeds a predefined cadence threshold value; 
 operating the electric drive motor under specification of (i) a second predefined target speed for the electric drive motor, which is higher than the first predefined target speed, and (ii) a second predefined torque for the electric drive motor, when a rider torque exerted by the rider on a drive train of the bicycle exceeds a first predefined rider torque threshold value; and 
 operating the electric drive motor under specification of a third predefined torque for the electric drive motor, when the rider torque exceeds a second predefined rider torque threshold value, which is higher than the first predefined rider torque threshold value, 
 wherein a freewheel is configured to couple the electric drive motor to the drive train of the bicycle, 
 wherein the first predefined torque and the second predefined torque are each maximum permissible torques and are set to provide substantially no drive support for the bicycle, and 
 wherein the third predefined torque is a target torque and is set to provide a predefined drive support for the bicycle. 
 
     
     
       2. The method according to  claim 1 , wherein:
 the predefined cadence threshold value corresponds to a value of five revolutions per minute to twenty-five revolutions per minute, 
 the first predefined target speed corresponds to a value of 60% to 99% of the predefined cadence of the rider, and/or 
 the second predefined target speed corresponds substantially to the predefined cadence of the rider. 
 
     
     
       3. The method according to  claim 1 , wherein:
 the first predefined rider torque threshold value corresponds to a value of 1 Nm to 9 Nm, 
 the second predefined rider torque threshold value corresponds to a value of 4 Nm to 15 Nm, and/or 
 the third predefined torque corresponds to at least twice the rider torque. 
 
     
     
       4. The method according to  claim 1 , wherein a transition between the second predefined torque and the third predefined torque is performed successively. 
     
     
       5. A method for controlling an electric drive motor of an electrically drivable bicycle comprising:
 determining a rider torque exerted by a rider of the bicycle on a drive train of the bicycle; 
 determining a cadence of the rider; 
 operating the electric drive motor under specification of (i) a third predefined target speed, and (ii) a fourth predefined torque for the electric drive motor when the determined rider torque is below a third predefined rider torque threshold value for a first predefined time period; and 
 operating the electric drive motor under specification of (i) a fourth predefined target speed, which is lower than the third predefined target speed, and (ii) a fifth predefined torque for the electric drive motor, when the determined rider torque is below a third predefined rider torque threshold value for a second predefined period of time, which is longer than the first predefined period of time, or when a number of pedal revolutions of the bicycle exceeds a predefined pedal revolution threshold value while the determined rider torque is below the third predefined rider torque threshold value, 
 wherein a freewheel is configured to couple the electric drive motor to the drive train of the bicycle, and 
 wherein the fourth predefined torque and the fifth predefined torque are each maximum permissible torques and are set to provide substantially no drive support for the bicycle. 
 
     
     
       6. The method according to  claim 5 , wherein:
 the third predefined target speed corresponds substantially to the determined cadence of the rider, and/or the third predefined rider torque threshold value corresponds to a value of 4 Nm to 15 Nm, and 
 the method further comprises deactivating the electric drive motor when the determined rider torque is below the third predefined rider torque threshold value for a third predefined period of time, which is longer than the first predefined period of time and the second predefined period of time, or when the determined rider cadence progressively slows down while the determined rider torque is below the third predefined rider torque threshold value. 
 
     
     
       7. The method according to  claim 1 , wherein a respective torque for the electric drive motor is set based on an estimated load applied to the electric drive motor. 
     
     
       8. The method according to  claim 1 , wherein a computer program is configured to perform the method. 
     
     
       9. The method according to  claim 8 , wherein a non-transitory machine-readable storage medium is configured to store the computer program. 
     
     
       10. The method according to  claim 1 , wherein an evaluation unit is configured to carry out the method.